Fix python scripts in src/tools/

tools/playback_benchmark/run.py

Index: tools/playback_benchmark/run.py
diff --git a/tools/playback_benchmark/run.py b/tools/playback_benchmark/run.py
old mode 100644
new mode 100755
index 231ee84740ed154b0486bd22af3766cf7330961c..04ed12bc0d3bc993f8c5f1633d0ce4df2965fefb
--- a/tools/playback_benchmark/run.py
+++ b/tools/playback_benchmark/run.py
@@ -1,8 +1,9 @@
 #!/usr/bin/env python
-#
-# Copyright 2010 Google Inc. All Rights Reserved.
+# Copyright (c) 2011 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
 
-"""Script for test playback.
+"""Tests playback.
 
 Prerequisites:
 1. OpenSSL library - http://www.openssl.org/
@@ -13,6 +14,7 @@ python run.py -t <test_dir>
 """
 
 from optparse import OptionParser
+import sys
 
 import playback_driver
 import proxy_handler
@@ -26,7 +28,7 @@ def Run(options):
   httpd.serve_forever()
 
 
-if __name__ == '__main__':
+def main():
   parser = OptionParser()
   parser.add_option("-t", "--test-dir", dest="test_dir",
                     help="directory containing recorded test data")
@@ -37,3 +39,6 @@ if __name__ == '__main__':
 
   Run(options)
 
+
+if __name__ == '__main__':
+  sys.exit(main())